The present invention relates generally to devices for controlling the rate of heat transfer between portions of the human body and the environment around the body. In some cases the invention is used primarily to reduce the amount of heat reaching the body from an unusually hot environment. In other cases the invention is used primarily to reduce the body temperature in a less hostile environment by absorbing heat from the body.
There are many industrial situations where individuals are required to work in hostile environments where the temperature is so high that it cannot reasonably be tolerated for a satisfactory period of time. This is particularly true where high temperature processes are being performed where the worker cannot be readily isolated from the processing itself or fr hot equipment or a surrounding hot environment. In such cases there is a need to keep radiant, conductive and/or convective heat from reaching the workers body, particularly the human trunk. Where the environmental temperature or heat level is extremely high, as near an open furnace or the like, the primary concern is to intercept a large amount of the heat which would otherwise reach the worker. This may be done by reflection and adsorption. Preferably the heat not reflected is dissipated as heat of fusion in melting a frozen material. Insulation may also be used between the heat source and the body to help control the amount of heat reaching the body.
It is essential that any equipment or garments used by a worker to protect his body by intercepting heat present a minimum burden during working conditions. If refreezable packs of heat absorptive material are used they must be easy to place in the equipment or garments and preferably be of uniform size to facilitate handling and replacement. A garment should be made so that inner faces of the refreezable packets of heat-absorptive material are held in good heat transfer relationship with the worker's body. If the equipment or garment is worn or carried it must be light weight, comfortable, efficient, and easily and practically maintained. This includes keeping it clean and sanitary. Usually industrial laundering is required with attendant harsh agitation is hot laundering liquids.
The prior art includes vest-like garments worn by workers to intercept heat while working in hostile environments. One such garment had generally straight-sided front and rear panel portions each of which had three horizontal different sized pockets containing removable packets of refreezable gel material. The packets were divided horizontally into three sections each containing an envelope of gel. When the gel was frozen solid the packets could bend where the sections were divided to give some flexibility to the packet. However this prior art garment had several deficiencies which have been overcome by the present invention. That garment was made of cotton duck with cotton bias binding around its periphery and it lost its shape during industrial laundering and had poor wear resistance both during laundering and during its intended use when worn to protect a person. It had a narrow elastic belt at each side of the body to interconnect front and rear parts of the vest. However, the belt would not remain flat when worn and was attached to the straight sides of the garment so that the forces from the belt were not distributed widely over a large vertical extent at both sides of the front and rear panel portions of the garment. Also, the relationship of insulating, reflective and heat absorptive materials was such that the heat was first intercepted by the insulation before it could be reflected and the reflective material was perforated so that not only was its surface not completely reflective, but also it permitted slight passage of heat therethrough by convection after the heat penetrated the insulation. Moreover, the in was in vertically spaced sections within the areas of the pockets and did not cover pocketed areas on the front and back of the garment. The insulation sections were significantly smaller than the periphery of the pockets and were not directly fastened to any other portion of the garment and could move around in the pockets and even curl up therein during laundering. Thus the insulation did not remain in fixed in alignment with the gel packets so that during use there were portions of the gel packets which were not protected by the insulation and there were spaces between the packets coinciding with spaces between the insulating sections where the only significant heat interceptor between the heat source and the worker was the perforated reflective material.